Collapsible extended surface filter and air cleaner system using collapsible extended surface filter

ABSTRACT

A collapsible air cleaner filter is provided. The filter includes a pleated media filter having a first end, a second end, and a filter media extending between the first and second ends, wherein the filter media includes a first plurality of flexible end portions and a second plurality of flexible end portions, the first and second plurality of flexible end portions are separated by a plurality of pleats, and the filter media extends a first length between the first and second plurality of flexible end portions, and an end member coupled to the first end of the pleated media filter, the end member extending a second length parallel to the first length, the first length being greater than the second length.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority as a continuation application of U.S.application Ser. No. 13/348,543, filed Jan. 11, 2012, which is acontinuation application of U.S. application Ser. No. 12/347,603, nowU.S. Pat. No. 8,157,881, filed Dec. 31, 2008, which claims the benefitof U.S. Provisional Patent Application 61/017,877, filed Dec. 31, 2007,the contents of which are hereby incorporated by reference in theirentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed to air cleaner assemblies incorporated intoforced air HVAC systems.

2. Related Art

Air cleaner assemblies for forced air heating, cooling and ventilation(HVAC) systems have been used for decades. Such air filtration devicesand structures vary widely from simple panel filters to twosubstantially different types of air cleaners: electronic air cleanersand extended surface pleated mechanical media filters. Extended surfacefilters can be supplied in a collapsible configuration or in a cartridgeconfiguration. Within the broad class of media filters, there is a widerange of filter media and structures. At one end of the conventionalrange of media filters are the relatively low-efficiency fiberglass orspun glass panel filters. These filters use a weave or felt of glassfibers to trap airborne particulates and the like. Typically, suchfiberglass mat filters have an American Society of Heating AirConditioning and Refrigeration Engineers (ASHRAE) average Arrestance of50-60%, per Standard 52.1. Such filters are typically one or two inchesthick. Pleated media filters are a step up from basic fiberglass matfilters. Such pleated media filters are typically thin synthetic orglass fiber sheets and typically have ASHRAE MERV ratings from 6-16, perStandard 52.2.

HVAC systems can use in-duct air cleaners. Such in-duct air cleanersinclude a frame or filter housing that connects to the inflow and/oroutflow portions of the duct work and an opening that allows a filter tobe inserted and removed from the air cleaner. Typically, the in-duct aircleaner is designed for a specific type and size of filter. The in-ductair cleaner typically includes a door or other panel that closes theopening of the filter housing through which the filter is inserted andremoved from the in-duct air cleaner.

SUMMARY OF THE DISCLOSED EMBODIMENTS

Collapsible extended surface pleated mechanical media (ESPM) filtersoccupy substantially less space in their collapsed state, compared toequivalent cartridge configurations. Thus, they are easier to store andship, and consequently have lower storage and shipping costs. However,collapsible ESPM filters are substantially less user-friendly thanequivalent cartridge-style filters, which can be easily inserted intoand removed from the filter housing with only minimal user interaction.

In contrast, collapsible ESPM filters can require substantial assemblyby the end user before they are ready to be installed into the filterhousing. For example, one such air cleaner design manufactured and soldby Research Products Corporation includes an inner housing, pleatspacers, an outer housing and a door. The ESPM filters for this aircleaner are sold in a collapsed state. Before the collapsible ESPMfilter can be installed, it must be opened up and assembled into theinner housing. The pleat spacers are then installed into the innerhousing and inserted into the opened ESPM filter to hold open thepleats. This adds significantly to the installation time and difficulty.The inner housing, ESPM filter and pleat spacers assembly is theninstalled into the outer housing. The outer housing and door have sealsthat provide a seal around the inner housing. This design has redundantsealing surfaces and many parts to install and is time consuming andlabor intensive to install.

Other collapsible ESPM filters are effectively collapsible cartridgefilters, in that they include components that, when assembled, act likethe cartridge housing of a cartridge-style filter. Companies having suchproducts include Honeywell, with its Pop-Up filter products and Carrier,with its EZ-Flex filter products. The Honeywell Pop-Up product comprisesmultiple molded plastic parts that are hinged and suspended on elasticcords that “Pop” into position to form a cartridge. The filter of theCarrier EZ-Flex product opens up like an accordion. Front and backpanels snap on the opened filter to form a cartridge. Both of thesedesigns have front and back panels forming a seal on the ends of thepleats. When these filters are installed into a housing, additionalseals are required between the front and back panels and the front andback walls of the housing. These seals represent additional parts anddesign complexity.

This invention provides an in-duct air cleaner having an easy-to-installcollapsible extended surface pleated media filter.

This invention separately provides an in-duct air cleaner having ahousing, where the collapsible extended surface pleated media filtereffectively self-seals against the front and rear walls of the housing.

This invention separately provides an in-duct air cleaner housing havingsupport members for a collapsible extended surface pleated media filter.

This invention separately provides an in-duct air cleaner having anenclosing structure, where the collapsible extended surface pleatedmedia filter has end members that form an effective seal against the topand bottom walls of the enclosing structure.

This invention separately provides an in-duct air cleaner having supportmembers for a collapsible extended surface pleated media filter.

In various exemplary embodiments of air cleaners according to thisinvention, an air cleaner comprises an enclosing structure having an airinlet surface, an air outlet surface, and at least one filter-openingsurface. In various exemplary embodiments, the enclosing structure ofthe air cleaner includes support members or the like provided adjacentto, but spaced a given distance from, the top and bottom walls of theenclosing structure. A collapsible extended surface pleated media filterhas a pair of end members and a mechanical media filter that extendsbetween the end members and is pleated.

The end members have an inner surface that the pleated mechanical mediafilter is attached to, and outer surface facing away from the pleatedmechanical media filter. The end members have a given thickness and agiven length that are appropriate for the particular enclosing structurethe collapsible extended surface pleated media filter is to be usedwith. In various exemplary embodiments, the thickness of the end membersis based on the distance of the support surfaces from the top and bottomwalls of the enclosing structure. In various exemplary embodiments, theend members have a seal structure provided on the outer surface thatinteracts with the top or bottom wall of the enclosing structure toprovide an effective seal against air flowing around, rather thanthrough, the collapsible extended surface pleated media filter.

In various exemplary embodiments, the mesh members have a width that isat most equal to the length of the end members. In various exemplaryembodiments, the pleated mechanical media filter has a width that isgreater than the length of the end members and/or width of the meshmembers. In such exemplary embodiments, the pleated mechanical mediafilter typically extends beyond both ends of the mesh and/or endmembers. In various other exemplary embodiments, a plurality of theflexible material strips extend between the end members, with at leastone flexible material strip located near, but spaced from, one or bothof the side edges of the pleated mechanical media filter. In suchexemplary embodiments, the pleated mechanical media filter extendsbeyond those flexible material strips and/or the ends of the endmembers.

To install a collapsible extended surface pleated media filter into theenclosing structure, the collapsible extended surface pleated mediafilter, if it is in a collapsed state, is expanded to an open state,typically by pulling apart the end members. The opened collapsibleextended surface pleated media filter is then inserted into theenclosing structure by inserting the end members of the collapsibleextended surface pleated media filter into the spaces between thesupport members and the top or bottom walls of the enclosing structure.In various exemplary embodiments, the length of the end members issubstantially equal to the depth of the enclosing structure between sidesurfaces of the enclosing structure, while the width of the pleatedmechanical media filter is greater than the depth of the enclosingstructure and the lengths of the end members and/or flexible supportmembers. As a result, a first portion of the width of the pleatedmechanical media filter that extends beyond the ends of the end membersadjacent to a back surface of the enclosing structure interacts with theback surface. Typically, that first portion of the pleated mechanicalmedia filter provides an effective seal between the collapsible extendedsurface pleated media filter and the back surface against air flowingaround, rather than through, the collapsible extended surface pleatedmedia filter.

Likewise, when a door or the like of the air cleaner is installed into afilter opening in the enclosing structure, the collapsible extendedsurface pleated media filter is held in the enclosing structure suchthat a second portion of the width of the pleated mechanical mediafilter that extends beyond the ends of the end members adjacent to thedoor interacts with the door. Typically, that second portion of thepleated mechanical media filter provides an effective seal between thecollapsible extended surface pleated media filter and the door againstair flowing around, rather than through, the collapsible extendedsurface pleated media filter. Accordingly, the collapsible extendedsurface pleated media filter fits into the enclosing structure such thatair passing through the air inlet surface, substantially and entirelypasses through the collapsible extended surface pleated media filter,and then passes out through the air outlet surface.

In various exemplary embodiments, the width of the pleated mechanicalmedia filter may be approximately equal to or slightly shorter than thedepth of the enclosing structure, such that the pleated mechanical mediafilter just contacts, or is even spaced a small distance away from, oneor both of the side surfaces of the enclosing structure. In still otherexemplary embodiments, the first and second ends of the pleatedmechanical media filter interact differently with the side surfaces ofthe enclosing structure. That is, one of the first and second endsextends substantially beyond the end of the end members, such that thatfirst or second end of the pleated mechanical media filter is pressedagainst the adjacent side surface of the enclosing structure. At thesame time, the other of the first and second ends just contacts or isspaced a sufficiently small distance from that other adjacent sidesurface. In both cases, the interaction of the ends of the pleatedmechanical media filter with the side surfaces of the enclosingstructure creates an effective seal such that the airflow through theenclosing structure substantially passes through the pleated mechanicalmedia filter rather than passing between the pleated mechanical mediafilter and the side surfaces.

In various exemplary embodiments of methods for using the collapsibleextended surface pleated media filter according to this invention, aused filter extending between the support members is removed from thesupport structure and discarded. A new collapsible extended surfacepleated media filter is removed from its packaging and expanded bypulling apart the end members. The end members are then inserted througha filter opening of the enclosing structure and into the spaces betweenthe support members and the top and bottom walls, such that the endmembers form an effective seal with the top and bottom walls of theenclosing structure against air flowing around, rather than through, thecollapsible extended surface pleated media filter. The collapsibleextended surface pleated media filter is pushed into the enclosingstructure such that a first portion of the pleated mechanical mediafilter is substantially adjacent to or contacts the back side surface ofthe enclosing structure to create an effective seal against air flowingaround, rather than through, the collapsible extended surface pleatedmedia filter. A door is then attached to the enclosing structure, suchthat a second portion of the pleated mechanical media filter issubstantially adjacent to or contacts the door to create an effectiveseal against air flowing around, rather than through, the collapsibleextended surface pleated media filter.

In various exemplary embodiments, the collapsible extended surfacepleated media filter optionally includes one or more flexible supportmembers or the like on or in the pleated mechanical media filter. Theflexible support members act to assist in keeping the pleats of thecollapsible extended surface pleated media filter open. The flexiblesupport members can be metal or formed of any other appropriatematerial. In various exemplary embodiments, the flexible support membersare mesh members. In various other exemplary embodiments, the flexiblesupport members are long, relatively narrow strips of flexible material.The flexible support members can be placed adjacent to one or both ofthe outer surfaces of the pleated mechanical media filter, and/or can beembedded within the pleated mechanical media filter.

In various exemplary embodiments, the mesh members have a width that isgenerally equal to the length of the end members. In various exemplaryembodiments, the pleated mechanical media filter has a width that isgreater than the length of the end members and/or width of the meshmembers. In such exemplary embodiments, the pleated mechanical mediafilter typically extends beyond both ends of the mesh members and/or endmembers. In various other exemplary embodiments, a plurality of theflexible material strips extend between the end members, with at leastone flexible material strip located near, but spaced from, one or bothof the side edges of the pleated mechanical media filter. In suchexemplary embodiments, the pleated mechanical media filter extendsbeyond those flexible material strips and/or the ends of the endmembers.

These and other features and advantages of various exemplary embodimentsof systems and methods according to this invention are described in, orare apparent from, the following detailed descriptions of variousexemplary embodiments of systems, methods and devices according to thisinvention.

BRIEF DESCRIPTION OF DRAWINGS

Various exemplary embodiments of systems, methods and devices accordingto this invention will be described in detail, with reference to thefollowing figures, wherein:

FIG. 1 is an isometric exploded view of a first exemplary embodiment ofa frame and a first exemplary embodiment of a collapsible extendedsurface pleated media filter according to this invention;

FIG. 2 is an isometric view of the first exemplary embodiment of thecollapsible extended surface pleated media filter shown in FIG. 1;

FIG. 3 is a front plan view of the first exemplary embodiment of theframe and the first exemplary embodiment of the collapsible extendedsurface pleated media of FIG. 1 showing the support members adjacent tothe top wall of the frame;

FIG. 4 is an isometric view of the first exemplary embodiment of theframe and the first exemplary embodiment of the collapsible extendedsurface pleated media filter shown in FIG. 1;

FIG. 5 is side cutaway view of the first exemplary embodiments of theframe and the extended surface pleated media filter of FIG. 1,illustrating how a first portion of the pleated mechanical filter mediainteracts with the rear surface of the frame and the door to form aneffective seal;

FIG. 6 is an isometric cutaway view of the first exemplary embodimentsof the frame and the extended surface pleated media filter of FIG. 1,illustrating how a second portion of the pleated mechanical filter mediainteracts with the rear surface of the frame and the door to form aneffective seal;

FIG. 7 is an isometric exploded view of a second exemplary embodiment ofa frame, a rail system and a second exemplary embodiment of acollapsible extended surface pleated media filter according to thisinvention;

FIG. 8 is an isometric view of the second exemplary embodiment of theextended surface pleated media filter of FIG. 7;

FIG. 9 is a front plan view of the second exemplary embodiments of theframe and the extended surface pleated media filter of FIG. 7 showingthe support members of the frame and the end members of the extendedsurface pleated media filter;

FIG. 10 is an isometric view of the second exemplary embodiment of theframe, the rail system and the second exemplary embodiment of thecollapsible extended surface pleated media filter shown in FIG. 7;

FIG. 11 is an isometric cutaway view of the second exemplary embodimentof the frame, the rail system and the second exemplary embodiment of thecollapsible extended surface pleated media filter shown in FIG. 7; and

FIG. 12 is an isometric view of a segment of ductwork and the railsystem and second exemplary embodiment of the collapsible extendedsurface pleated media filter shown in FIG. 7.

DETAILED DESCRIPTIONS OF EXEMPLARY EMBODIMENTS

The following detailed description of various exemplary embodiments ofin-duct air cleaners and collapsible extended surface pleated mediafilters according to this invention are described relative to acollapsible extended surface pleated media filter having end structuresand flexible support members (if provided) having the same generallength, with the wider pleated mechanical filter media extending beyondthe ends of the end structures and beyond any flexible support membersprovided on or relative to the pleated mechanical filter media. Itshould be appreciated that the length of the end structures and thewidth of the flexible support members need not be the same. It should beappreciated that, in such exemplary embodiments, the pleated mechanicalfilter media may extend beyond only one of the end structures and/or anyprovided flexible support member(s).

The following detailed description discusses exemplary embodiments wherethe enclosing structure is a frame having a top wall, bottom wall, rearwall and an opening for inserting the filter. The in-duct air cleanersand collapsible extended surface pleated media filters according to thisinvention do not require this, or any, specific enclosing structure. Forexample, the enclosing structure could be a segment of ductwork with atleast one filter-opening surface through which a collapsible extendedsurface pleated media filter can be installed. Alternatively, theenclosing structure can be a separate housing or frame or the like. Itshould be appreciated that the enclosing structure can be any structurethat can be installed in the path of the airflow or any other structurecapable of directing airflow largely through the collapsible extendedsurface pleated media filter, and that is capable of maintaining thecollapsible extended surface pleated media filter in position relativeto the airflow. The following detailed description assumes the openingis one vertically-oriented surface, and defines the “top”, “bottom” and“rear” walls accordingly. It should be appreciated that the openingcould instead be provided on a horizontally-oriented surface, with thevarious walls rotated accordingly.

FIG. 1 is an isometric exploded view of a first exemplary embodiment ofan in-duct air cleaner 10 according to this invention. As shown in FIG.1, the air cleaner 10 comprises a frame 100, as an enclosing structure,and a first exemplary collapsible extended surface pleated media filter200. As shown in FIG. 1, the frame 100 has a top wall 110, a bottom wall120 and a rear wall 130. In place of the other walls, the frame 100defines an air inlet surface 140, an air outlet surface 150, and afilter-opening surface 160. A door 170 is attachable to the frame 100 toclose the filter-opening surface 160. The air inlet and outlet surfaces140 and 150 are connected to an air outflow portion of the duct work andan air inflow portion of the duct work, respectively, of an HVAC system.It should be appreciated that, in the exemplary embodiment shown inFIGS. 1-6, a single filter-opening surface 160 and a single door 170 areprovided. In various other exemplary embodiments, alternate and/oradditional filter-opening surfaces 160 and doors 170 can be provided inplace of the top wall 110, the bottom wall 120 and/or the rear wall 130.

As shown in FIG. 1, the first exemplary collapsible extended surfacepleated media filter 200, when in an extended or open state, isinsertable into the frame 100 such that the first exemplary collapsibleextended surface pleated media (CESPM) filter 200 extends between thetop and bottom walls 110 and 120 and between the rear wall 130 and thefilter-opening surface 160. Consequently, when the filter-openingsurface 160 is closed by the door 170, air flowing into the air cleaner10 through the air inlet surface 140 preferentially passes through thefirst exemplary collapsible extended surface pleated media filter 200before exiting through the air outlet opening 150.

FIG. 2 is an isometric view of the first exemplary collapsible extendedsurface pleated media filter 200 shown in FIG. 1. As shown in FIG. 1,and as shown in greater detail in FIG. 2, the first exemplarycollapsible extended surface pleated media filter 200 includes a set ofend members or structures 210 and an extendible pleated mechanical mediafilter 220. In this exemplary embodiment, at least one flexible supportmember 230 is optionally placed in or on the pleated mechanical mediafilter 220, although the at least one flexible support member 230 can beomitted if desired. The one or more flexible support members 230 atleast help support the first exemplary collapsible extended surfacepleated media filter 200 in its extended state. In the exemplaryembodiment shown in FIGS. 1-6, the flexible support members 230 areimplemented as mesh members 230. At least one pleat spacer member 240extends along the pleat edges 226 of the pleated mechanical media filter220 between the end members or structures 210. The pleat spacermember(s) 240 are attached to the pleat edges 226, such as, for example,using an adhesive or by sonically welding the pleat spacer member(s) 240to the pleat edges 226. The pleat spacer member(s) 240 can also act asflexible support members in place of or in addition to the flexiblesupport members 230.

It should be appreciated that, in the exemplary embodiment shown inFIGS. 1-6, a single end member or structure 210 is attached to each endof the pleated mechanical media filter 220. In various other exemplaryembodiments, two or more end members or structures 210 can be attachedto, or formed using, each end of the pleated mechanical media filter220, with the end members or structures 210 arranged along the top andbottom edges of the pleated mechanical media filter 220. In yet otherexemplary embodiments, one end of the pleated mechanical media filter220 can be provided with a single end member or structure 210, while theother end of the pleated mechanical media filter 220 can be providedwith two or more end members or structures 210. In yet other exemplaryembodiments, rather than implementing the end members or structures 210as separate elements, the end members or structures 210 are formed atleast in part by combining a number of the pleats of the pleatedmechanical media filter 220 together as a unit. Such end members orstructures 210 similarly interact with the top and bottom walls 110 and120 to create an effective seal.

In the exemplary embodiment shown in FIGS. 1-6, the pleated mechanicalmedia filter 220 is a mat of synthetic fibers, while the mesh members230, if implemented, are made of metal wire. It should be appreciatedthat the pleated mechanical media filter 220 can be formed using anyknown or later-developed material, including synthetic fiber non-wovensheets, glass fiber non-woven sheets, combined synthetic and glass fibernon-woven sheets, natural fiber non-woven sheets, combinations of suchsheets, and the like.

FIG. 3 is a front plan view of the air cleaner 10 of FIG. 1 showing thesupport members 105 adjacent to the top wall 110 of the frame 100. Asshown in FIG. 1, and as shown in greater detail in FIG. 3, the frame 100has a first set of support members 105 located adjacent to the top wall110 and extending between the rear wall 130 and the filter-openingsurface 160 generally parallel to the air inlet and outlet surfaces 140and 150. Likewise, a second set of support members 105 are locatedadjacent to the bottom wall 120 and extending between the rear wall 130and the filter-opening surface 160 generally parallel to the air inletand outlet surfaces 140 and 150. It should be appreciated that thesupport members 105 do no need to contact the rear wall 130 and/or thedoor 170, and do not need to be continuous as they extend between therear wall 130 and the filter opening surface 160. In the first exemplaryembodiment shown in FIG. 3, the sets of support members 105 are spaced adesired or determined distance D_(s) from the top and bottom walls 110and 120, and are spaced from each other by a width W_(s). This createsspaces 107 between the top and bottom walls 110 and 120 and the supportmembers 105. It should be appreciated that the support members 105 cantake any appropriate shape that is able to maintain the end members orstructures 210 at the desired positions in the frame 100.

It should be appreciated that, as shown in FIGS. 1 and 3, the endmembers or structures 210 have a width W_(e) that is greater than thewidth W_(s) between the support members 105. Likewise, as shown in FIGS.1-3, the end members or structures 210 have any thickness T_(e) that isapproximately equal to or less than the distance D_(s) between thesupport members 105 and the top and bottom walls 110 and 120. As aresult, when the first exemplary collapsible extended surface pleatedmedia filter 200 is inserted into the frame 100, the end members orstructures 210 are held by the support members 105 in the spaces 107.

It should be further appreciated that, while the support members 105 areshown in FIG. 3 as simple brackets with an L-shaped cross section, thesupport members 105 may be any suitable support features that take anydesirable shape. In various other exemplary embodiments, the supportfeatures are a series of channels or grooves that interact with channelsor grooves provided on the end members or structures 210. In variousexemplary embodiments, the interaction between the end members orstructures 210 and the support features provides a tortuous path thatrestricts air flow between the end members or structures 210 and the topand/or bottom walls 110 and 120 to create an effective seal.

In the exemplary embodiment shown in FIGS. 1-6, the interaction betweenthe support members 105 and the adjacent edges of the end members orstructures 210 creates a flow path around the first exemplarycollapsible extended surface pleated media filter 200 that has a flowresistance that is higher than the flow resistance through the pleatedmechanical media filter 220, at least initially. Typically, the supportmembers 105 will extend substantially the entire distance between thefilter-opening surface 160 and the rear wall 130, although the supportmembers 105 need not do so. In various other exemplary embodiments, thedesired or determined distance D_(s) and the thickness T_(e) of the endmembers or structures 210 are selected so that, as shown in FIG. 4, whenthe first exemplary collapsible extended surface pleated media filter200 is inserted into the frame 100, an effective seal is formed betweenthe end members or structures 210 of the collapsible extended surfacepleated media filter 200 and the top and bottom walls 110 and 120 of theframe 100.

It should be appreciated that the term “effective seal” encompassesexemplary embodiments where, at least for a new, unused first exemplarycollapsible extended surface pleated media filter 200, the air flowingfrom the air inlet surface 140 to the air outlet surface 150preferentially passes through the pleated mechanical media filter 220,rather than above or below it. It should be appreciated that the term“effective seal” does not necessarily mean that no air flows betweeneither the support members 105 and the end members or structures 210and/or the end members or structures 210 and the top and/or bottom walls110 and/or 120.

Such exemplary embodiments include where each of the flow paths betweenthe end members or structures 210 and the top and bottom walls 110 and120 of the frame 100 has a flow resistance that is at least equal to theflow resistance through the pleated mechanical media filter 220, atleast for a new, unused first exemplary collapsible extended surfacepleated media filter 200. Such exemplary embodiments also include whereeach of the flow paths between the end members or structures 210 and thetop and bottom walls 110 and 120 of the frame 100 has a flow inertancethat is at least equal to the flow inertance through the pleatedmechanical media filter 220, at least for a new, unused first exemplarycollapsible extended surface pleated media filter 200.

It should be appreciated that, in various exemplary embodiments, atleast an outer surface 212 of each of the end members or structures 210of the first exemplary collapsible extended surface pleated media filter200 can be provided with seal structure(s) 214 that help create theeffective seal between the outer surfaces 212 of the end members orstructures 210 and the top and bottom walls 110 and 120. It should beappreciated that the seal structure 214 can be a surface treatment, acoating, a seal member or the like that interacts with an inner surfaceof the top or bottom walls 110 or 120 to create or provide the effectiveseal. Such a surface treatment can include roughening, and the like.Such a coating can include an elastomeric layer or the like. Such a sealmember can include a separate cork layer, foam layer, an elastomericlayer or the like that is adhesively attached to the outer surface 212.In various other exemplary embodiments, an effective seal may beprovided by a tortuous path between the end members or structures 210,the top and/or bottom walls 110 and 120 and/or the support members 105.Such a tortuous path is usable to limit airflow between the end membersor structures 210 and the bottom walls 110 and 120. The tortuous pathwill typically increase the flow resistance of the flow path between theend members or structures 210 and the top and/or bottom walls 110 and120.

It should be appreciated that the top end member or structures 210 andthe bottom end member or structures 210 do not have to have a sealstructure, and do not need to have the same type of seal structure ifthe seal structure is implemented. For example, a tortuous path betweenthe end members or structures 210 and the top and/or bottom walls 110and 120 may provide an effective seal without the use of the sealstructure. It should also be appreciated that a seal structure can beprovided on the inner surfaces of one or both of the top and/or bottomwalls 110 and/or 120, either in place of or in addition to the sealstructure provided on the outer surfaces 212 of the end members orstructures 210.

FIGS. 5 and 6 are side cross-sectional and isometric cutaway views ofthe air cleaner 10, respectively. In particular, FIGS. 5 and 6illustrate how this exemplary embodiment of the pleated mechanical mediafilter 220 preferably interacts with the rear wall 130 and the door 170to provide effective seals between the pleated mechanical media filter220 and the rear wall 130 and the door 170. FIG. 6 shows a partialcutaway view of the first exemplary collapsible extended surface pleatedmedia filter 200 installed in the frame 100, showing how end portions ofthe width of the pleated mechanical media filter 220 can be bent orpressed against the rear wall 130 to provide an effective seal.

It should be appreciated that, in the exemplary embodiment shown inFIGS. 1-6, the pleated mechanical media filter 220 has a width W_(f)that is greater than the length L_(e) of the end members or structures210 and the width W_(m) of the mesh members 230. Additionally, thepleated mechanical media filter 220 is positioned relative to the endmembers or structures 210 and the mesh members 230 such that the pleatedmechanical media filter 220 has first and/or second portions 222 and/or224 that extend beyond both ends of the end members or structures 210and the mesh members 230. It should further be appreciated that, in theexemplary embodiment shown in FIGS. 1-6, both the width W_(m) of themesh members 230 and the length L_(e) of the end members or structures210 are approximately equal to a depth D_(f) of the frame 100.

Accordingly, as shown in FIGS. 5 and 6, after the first exemplarycollapsible extended surface pleated media filter 200 is fully insertedinto the frame 100, the first and/or second portions 222 and/or 224 ofthe pleated mechanical media filter 220 are trapped between the meshmember(s) 230 and the rear wall 130 and/or the door 170, respectively.That is, when the first exemplary collapsible extended surface pleatedmedia filter 200 is fully inserted into the frame 100, the first portion222 (if present) of the pleated mechanical media filter 220 pressesagainst the rear wall 130, forming an effective seal with the rear wall130. Likewise, when the door 170 is attached to the frame 100 to closethe filter-opening surface 160, the second portion 224 (if present) ofthe pleated mechanical media filter 220 presses against the door 170,forming an effective seal with the door 170.

It should be appreciated that the first and second portions 222 and 224may also include a connecting portion, such as a cloth member, thatconnects an edge of each of the pleats together. The connectingportion(s), if present, typically help create the effective seal(s)between the first and/or second portions 222 and/or 224 and the rearwall 130 or door 170.

It should be appreciated that the term “effective seal” againencompasses exemplary embodiments where, at least for a new, unusedfirst exemplary collapsible extended surface pleated media filter 200,the air flowing from the air inlet surface 140 to the air outlet surface150 preferentially passes through the pleated mechanical media filter220, rather than to either side of it. It should be appreciated thatterm “effective seal” does not necessarily mean that no air flowsbetween the first and/or second portions 222 and/or 224 of the pleatedmechanical media filter 220 and the rear wall 130 and/or the door 170.

It should be further appreciated that the term “effective seal” does notrequire that the pleated mechanical media filter 220 touch the rear wall130 and/or the door 170. An effective seal can be created between thepleated mechanical media filter 220 and the rear wall 130 and/or thedoor 170 whenever the pleated mechanical media filter 220 issufficiently close to the rear wall 130 and/or the door 170, such that avast majority of the airflow is directed through the pleated mechanicalmedia filter 220 rather than between the pleated mechanical media filter220 and the rear wall 130 and/or the door 170.

Additionally, the rear wall 130 and/or the door 170 may include asealing surface or structure provided on the rear wall 130 and/or on thedoor 170. The sealing surface or structure may be similar to the sealstructure previously discussed with regard to the end members orstructures 210. If present, the sealing surface or structure typicallyhelps create the effective seal between the first and/or second portions222 and 224 and the rear wall 130 and/or the door 170.

FIG. 7 shows a second exemplary embodiment of the air cleaner 10,including the frame 100 with an exemplary embodiment of a rail system190 and a second exemplary collapsible extended surface pleated mediafilter 300. As shown in FIG. 7, the rail system 190 can be inserted intothe frame 100 to provide support structures for the second exemplarycollapsible extended surface pleated media filter 300.

It should be appreciated that the rail system 190 may be usable as anupgrade kit to allow the second exemplary collapsible extended surfacepleated media filter 300 to be installed in the frame 100 even if theframe 100 was not originally compatible with the second exemplarycollapsible extended surface pleated media filter 300.

In the exemplary embodiment shown in FIG. 7, the rail system 190includes four support arms 192 and two rail guides 194. The support arms192 and the rail guides 194 can be keyed or otherwise manufactured sothat they can only be put together in the desired orientation. Thesupport arms 192 couple with the rail guides 194 to provide an enclosingstructure for the second exemplary collapsible extended surface pleatedmedia filter 300. In contrast to the exemplary embodiment shown in FIGS.1-6, in the exemplary embodiment shown in FIGS. 7-11, the rail system190 interacts with the frame 100 to provide the enclosing structure.

The rail guides 194 further include flexible tabs 195. The flexible tabs195 are usable to help hold the rail guides 194 in a fixed positionwithin the frame 100. During installation, the support arms 192 areinserted into slots in the rail guides 194 to provide the generallybox-shaped rail system 190. The rail system 190 is inserted into theframe 100 and one or more of the flexible tabs 195 on one or more of therail guides 194 are bent towards the frame 100. By bending one or moreof the flexible tabs 195 toward the frame 100, the one or more flexibletabs 195 will prevent the rail system 190 from being inadvertentlyremoved from the frame 100. It should be appreciated that the railguides 194 may include multiple flexible tabs 195 of different lengths.The different lengths of the various flexible tabs 195 may be usable toinstall the same rail system 190 into different frames 100 withdifferent internal dimensions.

As shown in FIG. 7, the second exemplary collapsible extended surfacepleated media filter 300, when in the extended or open state, isinsertable into the rail system 190 such that the second exemplarycollapsible extended surface pleated media filter 300 extends betweenthe rail guides 194 and between the rear wall 130 and the filter-openingsurface 160 of the frame 100.

FIG. 8 is an isometric view of the second exemplary collapsible extendedsurface pleated media filter 300 shown in FIG. 7. As shown in FIG. 8,the second exemplary collapsible extended surface pleated media filter300 includes a set of end members or structures 310 and an extendiblepleated mechanical media filter 320. It should be appreciated that thesecond exemplary collapsible extended surface pleated media filter 300may also include structures similar to the flexible support member 230and the pleat spacer members 240 of the first exemplary collapsibleextended surface pleated media filter 200 shown in FIG. 2.

FIG. 9 is a front cross-sectional view of the rail system 190 and thesecond exemplary collapsible extended surface pleated media filter 300installed in the frame 100 showing the interactions between one of therail guides 194 of the rail system 190, the top wall 110 of the frame190 and one of the end members or structures 310 of the second exemplarycollapsible extended surface pleated media filter 300. As shown in FIG.9, the rail guide 194 interacts with a rib 112 on the top wall 110 ofthe frame 100. Likewise, another rail guide 194 may interact with asimilar rib on the bottom wall 120 of the frame 100. The rib 112 helpshold the rail system 190 in a fixed position relative to the frame 100.The end members or structures 310 include feet 312 that interact withedges 196 of the rail guides 194. The feet 312 and the edges 196 helphold the second exemplary collapsible extended surface pleated mediafilter 300 in a fixed position relative to the rail system 190, and thusthe frame 100. The feet 312, the edges 196, the top and/or bottom walls110 and/or 120 and/or other structures of the end members or structures310 or rail system 190 may also help provide an effective seal betweenthe end members or structures 310 and the top and/or bottom walls 110and/or 120 by helping provide a tortuous path between the end members orstructures 310 and the top and/or bottom walls 110 and/or 120.

FIG. 10 shows the second exemplary collapsible extended surface pleatedmedia filter 300 being installed into the frame 100. It should beappreciated that FIG. 10 shows the rail system 190 pulled out from theframe 100 to better show the interactions between the frame 100, therail system 190 and the second exemplary collapsible extended surfacepleated media filter 300. In general, the rail system 190 will beinstalled into the frame 100 separately from the second exemplaryextended surface pleated media filter 300 and will not beremoved/replaced with subsequent removal/replacement of the secondexemplary collapsible extended surface pleated media filter 300.

FIG. 11 shows an isometric cutaway view of the second exemplarycollapsible extended surface pleated media filter 300 installed into therail system 190 and the frame 100. As shown in FIG. 11, the pleatedmechanical media filter 320 of the second exemplary collapsible extendedsurface pleated media filter 300 includes first and/or second portions322 and/or 324 that interact with the rear wall 130 and/or the door 170of the frame 100 in a similar manner as the first and/or second portions222 and/or 224 of the first exemplary collapsible extended surfacepleated media filter 200 shown in FIGS. 1-6.

As shown in FIG. 11, after the second exemplary collapsible extendedsurface pleated media filter 300 is fully inserted into the frame 100,the first and/or second portions 322 and/or 324 of the pleatedmechanical media filter 320 are pressed against the rear wall 130 and/orthe door 170. It should be appreciated that, if the pleated mechanicalmedia filter 320 includes structures similar to the flexible supportmember(s) 230 of the first exemplary collapsible extended surfacepleated media filter 200, the first and/or second portions 322 and/or324 may be further forced toward the back wall 130 and/or door 170 bysuch structures. As such, when the second exemplary collapsible extendedsurface pleated media filter 300 is fully inserted into the frame 100,the first portion 322 (if present) of the pleated mechanical mediafilter 320 presses against the rear wall 130, forming an effective sealwith the rear wall 130. Likewise, when the door 170 is attached to theframe 100 to close the filter-opening surface 160, the second portion324 (if present) of the pleated mechanical media filter 320 pressesagainst the door 170, forming an effective seal with the door 170.

It should be appreciated that the first and second portions 322 and 324may also include a connecting portion, such as a cloth member, thatconnects an edge of each of the pleats together. The connectingportion(s), if present, typically help create the effective seal(s)between the first and/or second portions 322 and/or 324 and the rearwall 130 or door 170.

FIG. 12 shows the second exemplary collapsible extended surface pleatedmedia filter 300 and the rail system 190 being inserted into a segmentof ductwork. In the embodiment shown in FIG. 12, the walls of theductwork are usable as the top wall 110, the bottom wall 120 and therear wall 130 (not shown). Likewise, the door 170 may be at leastpartially formed from a portion of the ductwork. It should beappreciated that the rib(s) 112 may be elements of the ductwork or maybe separate elements coupled with the ductwork (e.g., welded to theductwork, bolted to the ductwork, etc.) and may be any known orlater-developed element or structure that is usable to keep the railsystem 190 in a substantially fixed location relative to the segment ofductwork. As shown in FIG. 12, an existing or new segment of ductworkmay be used as an enclosing structure for the collapsible extendedsurface pleated media filter 200 or 300. In one exemplary embodiment, ahole is cut into an existing segment of ductwork to provide thefilter-opening surface 160.

The preceding detailed description discussed exemplary embodiments wherethe flexible support members, when provided, are implemented as meshmembers. It should be appreciated that any known or later developeddevice, structure and/or material that can appropriately support thepleated mechanical filter media at least in the extended or open stateand which is sufficiently flexible to allow the collapsible extendedsurface pleated media filter to be altered between a collapsed state andthe extended state a plurality of times may be used as the flexiblesupport members. For example, as outlined above, the flexible supportmembers may alternatively be implemented as long, relatively narrowstrips formed of a flexible material. Additionally, the pleatedmechanical media filter may be formed using appropriate materials suchthat the pleated mechanical media filter is stiff enough to maintain thedesired shape without the need of a support structure. Alternatively, asupport structure may be incorporated into the enclosing structure. Sucha support structure could include one or more support beams locatedbetween two or more surfaces of the enclosing structure, to providesupport for the pleated mechanical media filter.

It should also be appreciated that, if one or more flexible supportmembers are implemented as one or more mesh members, only one meshmember may be used, and that mesh member may be placed adjacent to oneside of the pleated mechanical filter media or embedded within thepleated mechanical filter media. It should further be appreciated thatthe pleated mechanical filter media may extend beyond only one end ofthe end members/structures and/or the flexible support member(s). Itshould also be appreciated that the pleated mechanical filter media canhave any desired thickness.

It should be appreciated that any known or later-developed technique canbe used to embed one or more flexible support members in the pleatedmechanical filter media. For example, the flexible support member can beembedded by forming the pleated mechanical filter media using two layersof filter material, with the flexible support member located between thetwo layers. It should also be appreciated that the flexible supportmembers are optional, and may be omitted entirely. Thus, it should beappreciated that the particular set of end members/structures, flexiblesupport members and pleated mechanical filter media described in thepreceding exemplary embodiments are illustrative only.

Similarly, it should be appreciated that the flexible support members,if implemented, can be formed of any known or later-developed materialthat has the desired stiffness, including metals, whether single elementmetals or alloys, synthetic fibers, natural fibers or the like. Itshould be appreciated that the flexible support members can be providedon one or both sides of the pleated mechanical media filter, and/or canbe embedded within the pleated mechanical media filter.

While this invention has been described in conjunction with theexemplary embodiments outlined above, various alternatives,modifications, variations, improvements and/or substantial equivalents,whether known or that are or may be presently foreseen, may becomeapparent to those having at least ordinary skill in the art.Accordingly, the exemplary embodiments of the invention, as set forthabove, are intended to be illustrative, not limiting. Various changesmay be made without departing from the spirit or scope of the invention.Therefore, the invention is intended to embrace all known or earlierdeveloped alternatives, modifications, variations, improvements and/orsubstantial equivalents.

What is claimed is:
 1. A collapsible air cleaner filter comprising: a collapsible pleated media filter having a first end, a second end, and a filter media extending between the first and second ends, wherein the filter media includes a plurality of pleats having a first plurality of flexible width portions and a second plurality of flexible width portions, the filter media having a width extending between and including the first and second plurality of flexible width portions; a first end member coupled to and extending along the first end of the collapsible pleated media filter, the first end member having a structural body with a cross sectional shape generally defining at least one outwardly projecting first end foot member, the at least one outwardly projecting first end foot member at least partially defining at least one first end retaining channel, wherein the at least one first end retaining channel is adapted to receive a portion of a first rail provided in a first portion of an air duct; and a second end member coupled to and extending along the second end of the collapsible pleated media filter, the second end member having a structural body with a cross sectional shape generally defining at least one outwardly projecting second end foot member, the at least one outwardly projecting second end foot member at least partially defining at least one second end retaining channel, wherein the at least one second end retaining channel is adapted to receive a portion of a second rail provided in a second portion of an air duct and wherein the collapsible pleated media filter is adapted to be expanded to an open state by pulling the first and second end members apart to engage the first and second rails.
 2. The collapsible air cleaner filter of claim 1, further comprising at least one first rib extending angularly from the first end member away from the collapsible pleated media filter, and at least one second rib extending angularly from the second end member away from the collapsible pleated media filter.
 3. The collapsible air cleaner filter of claim 2, wherein a portion of the at least one first rib is generally perpendicular to the first end member, and a portion of the at least one second rib is generally perpendicular to the second end member.
 4. The collapsible air cleaner filter of claim 2, wherein the at least one first rib extends generally parallel to the at least one first end foot member, and the at least one second rib extends generally parallel to the at least one second end foot member.
 5. The collapsible air cleaner filter of claim 1, wherein: the at least one first end foot member includes a first portion provided generally perpendicular to the first end member and a second arcuate portion connected to the first portion, the first portion, second portion, and first end member defining the at least one first end retaining channel; and the at least one second end foot member includes a third portion provided generally perpendicular to the second end member and a fourth arcuate portion connected to the third portion, the third portion, fourth portion, and second end member defining the at least one second end retaining channel.
 6. The collapsible air cleaner filter of claim 1, further comprising: a rail assembly for retaining the collapsible pleated media filter within an air duct, the rail assembly including a first rail guide coupled to a first wall of the air duct and a second rail guide coupled to a second wall of the air duct, the first rail guide including a first rail edge, and the second rail guide including a second rail edge, wherein: the collapsible pleated media filter is retained by the rail assembly such that the first rail edge is received by the at least one first end retaining channel, and the second rail edge is received by the at least one second end retaining channel.
 7. The collapsible air cleaner filter of claim 1, further comprising a rail system provided in a portion of an air duct, the rail system having a first rail guide spatially opposing a second rail guide, the first rail guide having a first rail edge and the second rail guide having a second rail edge, wherein the first rail edge is removably received by the first end retaining channel of the first end foot member and the second rail edge is removably received by the second end retaining channel of the second end foot member such that the collapsible pleated media filter is retained in an extended position between the first and second rail guides.
 8. The collapsible air cleaner filter of claim 7, further comprising an air duct having a first wall, a second wall, an air inlet surface, and an air outlet surface, the first rail guide being coupled to the first wall and provided between the air inlet surface and the air outlet surface, the second rail guide being coupled to the second wall and provided between the air inlet surface and the air outlet surface, wherein the collapsible pleated media filter is provided across the air duct between the air inlet surface and the air outlet surface, forming an effective seal between the first end member and the first wall, and an effective seal between the second end member and the second wall.
 9. The collapsible air cleaner filter of claim 8, further comprising: a first rib coupled to the first wall and projecting toward the second wall; a first channel provided on the first rail guide; a second rib coupled to the second wall and projecting toward the first wall; and a second channel provided on the second rail guide; wherein the first channel receives the first rib, forming an effective seal by a tortuous path between the first rail guide and the first wall, and second channel receives the second rib, forming an effective seal by a tortuous path between the second rail guide and the second wall.
 10. The collapsible air cleaner filter of claim 8, wherein the effective seal between the first end member and the first wall of the air duct is formed by a tortuous path between engaged portions of the first end member and the first rail guide, and the effective seal between the second end member and the second wall of the air duct is formed by a tortuous path between engaged portions of the second end member and the second rail guide.
 11. The collapsible air cleaner filter of claim 1, wherein the first and second end members are substantially shape retaining.
 12. A collapsible air cleaner filter comprising: a collapsible pleated media filter having a first end, a second end, and a filter media extending between the first and second ends, wherein the filter media includes a plurality of pleats having a first plurality of flexible width portions and a second plurality of flexible width portions, the filter media having a width extending between and including the first and second plurality of flexible width portions; a first end member coupled to and extending along the first end of the collapsible pleated media filter, the first end member having a structural body with a cross sectional shape generally defining at least one outwardly extending first end foot member, the at least one first end foot member at least partially defining at least one first end retaining channel; a second end member coupled to and extending along the second end of the collapsible pleated media filter, the second end member having a structural body with a cross sectional shape generally defining at least one outwardly extending second end foot member, the at least one second end foot member defining at least one second end retaining channel; and a rail assembly for retaining the collapsible pleated media filter within an air duct, the rail assembly including a first rail guide coupled to a first wall of the air duct and a second rail guide coupled to a second wall of the air duct, the first rail guide including a first rail edge, and the second rail guide including a second rail edge, wherein: the collapsible pleated media filter is adapted to be expanded to an open state by pulling the first end member relative to the second end member and retained by the rail assembly such that the first rail edge is received by the at least one first end retaining channel, and the second rail edge is received by the at least one second end retaining channel.
 13. The collapsible air cleaner filter of claim 12, further comprising at least one first rib extending angularly from the first end member away from the collapsible pleated media filter, and at least one second rib extending angularly from the second end member away from the collapsible pleated media filter.
 14. The collapsible air cleaner filter of claim 13, wherein a portion of the at least one first rib is generally perpendicular to the first end member, and a portion of the at least one second rib is generally perpendicular to the second end member.
 15. The collapsible air cleaner filter of claim 13, wherein the at least one first rib extends generally parallel to the at least one first end foot member, and the at least one second rib extends generally parallel to the at least one second end foot member.
 16. The collapsible air cleaner filter of claim 12, wherein: the at least one first end foot member includes a first portion provided generally perpendicular to the first end member and a second arcuate portion connected to the first portion, the first portion, second portion, and first end member defining the at least one first end retaining channel; and the at least one second end foot member includes a third portion provided generally perpendicular to the second end member and a fourth arcuate portion connected to the third portion, the third portion, fourth portion, and second end member defining the at least one second end retaining channel.
 17. A collapsible air cleaner filter comprising: a collapsible pleated media filter having a first end, a second end, and a filter media extending between the first and second ends, wherein the filter media includes a plurality of pleats having a first plurality of flexible width portions and a second plurality of flexible width portions, the filter media having a width extending between and including the first and second plurality of flexible width portions; a first end member coupled to and extending along the first end of the collapsible pleated media filter, the first end member having a structural body with a cross sectional shape generally defining an outwardly extending first end foot member and an outwardly extending second end foot member, the first and second end foot members extend angularly from the first end member away from the collapsible pleated media filter, the first end foot member defining a first end retaining channel, and the second end foot member defining a second end retaining channel; and a second end member coupled to and extending along the second end of the collapsible pleated media filter, the second end member having a structural body with a cross sectional shape generally defining an outwardly extending third end foot member and an outwardly extending fourth end foot member, the third and fourth end foot members extend angularly from the second end member away from the collapsible pleated media filter, the third end foot member defining a third end retaining channel, and the fourth end foot member defining a fourth end retaining channel; wherein the collapsible pleated media filter is expandable to an open state by pulling the first end member relative to the second end member; and wherein the first and second retaining channels are adapted to receive a first portion of a rail assembly provided separate from the collapsible air cleaner filter to form an effective seal through a tortuous path between the first end member and the rail assembly, and the third and fourth retaining channels are adapted to receive a second portion of the rail assembly provided separate from the collapsible air cleaner filter to form an effective seal through a tortuous path between the second end member and the rail assembly.
 18. The collapsible air cleaner filter of claim 17, further comprising at least two first ribs extending outwardly from the first end member, the at least two first ribs being provided between the first and second end foot members, and at least two second ribs extending outwardly from the second end member, the at least two second ribs being provided between the third and fourth end foot members.
 19. The collapsible air cleaner filter of claim 17, wherein the first and second end members do not completely overlap the first and second plurality of flexible width portions.
 20. The collapsible air cleaner filter of claim 17, further comprising a rail system separate from the collapsible pleated media filter, the rail system having a first rail guide spatially opposing a second rail guide, the first rail guide having a first and second rail edge and the second rail guide having a third and fourth rail edge, wherein the first rail edge removably engages the first end retaining channel, the second rail edge removably engages the second end retaining channel, the third rail edge removably engages the third end retaining channel, and the fourth rail edge removably engages the fourth end retaining channel such that the pleated media filter is retained in an extended position between the first and second rail guides. 